The objectives are to explore the roles of the maternal and foetal pituitary adrenal systems and the interaction of maternal and foetal genotypes in mediating the effects of prenatal stress on offspring behavior in rats. Females with pituitary-adrenal function altered by adrenalectomy or by the administration of adrenocorticotrophin or dexamethasone receive daily electric shocks during gestation. Litters are fostered at birth to minimize differential postnatal maternal effects. Pituitary-adrenocortical function of their offspring is assessed neonatally and in adulthood. Dependent behavioral measures include a reaction-to-handling test, open-field activity and defecation, and passive and active avoidance conditioning measures. To asses the roles of foetal and maternal genotype ova transplantation will be used to obtain all possible foetal genotype-maternal genotype combinations. Appropriate controls will be used to assess the effects of ova transplantation itself. Half the females in each group will be stressed during gestation and pituitary-adrenocortical and behavioral data obtained on offspring.